While I was in college,my hall started a tradition of building rafts to take on the Charles River to watch Boston's 4th of July fireworks. In the summer of 2004, I decided to build one, too. I didn't really have a concept for the raft/boat until a trip to Home Depot, when I found 100' rolls of PVC landscaping drainage pipe. I decided to make a raft out of a coil of the pipe: just a flat platform, with an inflatable kiddie pool in the middle, to keep anything dry that needed to stay that way. So, I got some end-caps for the pipe, some Great Stuff spray foam insulation to seal the ends, and some rope to lash the coils together. When we got back to East Campus, I lashed the pipe together into a tight coil with some rope, then took it outside and sealed the ends with the Great Stuff, using the leftover foam to fill in the gaps in the underside. After that dried and I had to move the raft again, I found that the raft was still too flexible for my liking, so I got some 1/8" plywood sheeting and lashed some pieces of that into place, to keep the pipe from shifting around so much.

We got off to a late start on the 4th, and on our way through the crowds to get to where we were going to drop our rafts into the river, we were stopped around 7 times. First by the Cambridge Police, then Cambridge Fire, then the State Patrol, then more Cambridge Fire, more State Patrol, the National Guard, and finally the State Patrol again, for the last time. Although there were other makeshift rafts out on the river, and we had all of the safety equipment required by the state, we weren't allowed to take the rafts out. So, we had to bring them back to EC, and let them sit.

Finally, in August, I got sick of having the thing on the floor of my room, and got a friend to go out on the raft with me (along with a group of people to watch/take photos). We launched from a canal behind the HP building in Kendall Square, and started paddling out toward the river. After a few seconds, we noticed a few problems: first, the raft was still too compliant, and the pipes would move away from you, leaving you supported, but wet, and second, we had forgotten to bring life jackets along, which are required for travelling on the river. So, once we got to the dock just outside the mouth of the canal, we pulled the raft out, and noticed that it was much heavier than it had been. It seems that the Great Stuff wasn't a great sealant, and around 40 or 50 lbs worth of water had gotten inside, and made the raft ride even lower in the water. I calculated that, with the volume of air inside the tube, the raft should have been able to hold around 500 lbs above water, which I think it could have, had it been properly sealed and stiffened. It was pretty uncomfortable to ride so close to the water, so I decided not to improve the raft.